The invention relates to a device and method for performing a printing plate change on a plate cylinder of a printing press.
German Patent Document No. DE 44 40 239 C2 discloses a device embodied as a rolling element for performing a printing plate change on a plate cylinder of a printing press. The rolling element disclosed there is used when changing the printing plate to press a flexible printing plate on the plate cylinder of a printing couple of a printing press. The rolling element in accordance with DE 44 40 239 C2 has several rollers that can be individually engaged on the plate cylinder that are arranged in the longitudinal direction of the plate cylinder, wherein at least one first roller can be engaged when mounting the printing plate and at least one second roller can be engaged when dismounting the printing plate in the region of the printing plate on the plate cylinder. It is possible with the rolling element in accordance with DE 44 40 239 C2 to precisely press the printing plate on the plate cylinder when changing the printing plates, but the device in accordance with the prior art does not permit precise alignment of the printing plate relative to the plate cylinder.
A device for performing a printing plate change on a plate cylinder of a printing press is known from German Patent Document No. DE 10 2004 022 083 B3, which features an alignment element on each of the two sides of the rolling element featuring several rollers in order to align a to-be-clamped printing plate relative to the plate cylinder when changing a printing plate. In this case, the alignment elements have a gripper and a clamping piece cooperating with the gripper, whereby a to-be-clamped printing plate can be clamped between the gripper and the clamping piece.
Starting from here, the present invention is based on the objective of creating a novel device and method for performing a printing plate change on a plate cylinder of a printing press.
According to the invention, a strip bearing several alignment elements extends parallel to the rolling element, wherein a printing plate can be aligned true to register between every two adjacent alignment elements before the printing plate is clamped in a lockup slot of the plate cylinder.
With the inventive device and method, it is possible to simultaneously align several printing plates true to register relative to the plate cylinder before the printing plates are clamped on the plate cylinder. In addition, the device in accordance with the invention is structurally simple and can be realized at a relatively low cost.
At least two centering pins are preferably allocated to the strip, which is upstream from the rolling element, and these pins can be inserted into corresponding recesses of the plate cylinder to align the strip and therefore the alignment elements relative to the plate cylinder.
According to an advantageous development of the invention, clamping elements extend between adjacent alignment elements, wherein a printing plate, which is to be clamped in the lockup slot of the plate cylinder and which is to be aligned true to register on the corresponding alignment elements, can be held down by each clamping element during a printing plate change.
When the strip and therefore the alignment elements are aligned relative to the plate cylinder for the printing plate change, a lower edge of the clamping elements is at a distance from a surface of the plate cylinder that is greater than the thickness of a printing plate so that a printing plate can be fed between a clamping element and the plate cylinder and can be moved in the direction towards the corresponding alignment elements, and a lower edge of the strip is at a distance from a surface of the plate cylinder that is less than the thickness of the printing plate so that the printing plate cannot be fed between the strip and the plate cylinder.
Preferred developments of the invention are yielded from the following description. Without being limited hereto, one exemplary embodiment of the invention is explained in greater detail on the basis of the drawings.